1. Field of the Invention
The invention relates to a control apparatus and method for a power supply mounted in a vehicle. More specifically, this invention relates to technology for supplying power for a fixed period when vehicle starting means is switched from on to off.
2. Description of the Related Art
Steering apparatuses, braking apparatuses, and shifting apparatuses, are all examples of apparatuses which control the behavior of a vehicle. When these apparatuses are electronically controlled apparatuses that are controlled electrically, they are generally connected, via an ignition switch which serves as vehicle starting means, to a power supply for the vehicle, from which they receive power. Therefore, when the ignition switch is turned from on to off, the power supplied to those electronically controlled apparatuses also turns off. Technology is known, such as that disclosed in Japanese Utility Model Publication No. JP-U-5-32374, which relates to a self-maintaining function that supplies power to these kinds of electronically controlled apparatuses for a fixed period of time after the ignition switch is turned off.
The technology disclosed in the aforementioned publication provides a switch which interrupts the supply of power to an electronic control unit that controls the electronically controlled apparatuses, thereby reducing the amount of power from the power supply that is consumed.
With the technology in that publication, however, only simple two-way control of either supplying power or interrupting the supply of power is achieved; fine control according to the state of the vehicle is not possible.